Handbook of Silicon Based MEMS Materials and Technologies

2.7. Magnetic Fields

There are two different kinds of static magnetic fields in widespread use to produce CZ silicon crystals, transverse and cusp fields. Almost pure axial fields are poorly suited, as they tend to prevent transport of oxygen and dopant from under the crystal; and, therefore, the resulting oxygen concentration is high and variation of oxygen and dopant in the radial direction (radial gradients) is often large.

Magnets weigh usually several tons, and the power may be well beyond 100 kW. However, more power-hungry magnets have been increasingly replaced with superconducting magnets. Sometimes, especially older growers have been modified to take more lightweight magnets, despite the cost of higher electric current density and ...